London, December 8 (ANI): Psy, who's song 'Gangnam Style' is the most-watched YouTube video of all time with over 900 million views, may be about to lose much of his popularity in the U.S, it has been revealed.

It has just come to light that the artist used to rap about "slowly and painfully" killing American soldiers and their families.

The performer has also apologized for his words in 2004.

During an anti-American protest in Seoul in 2002 Psy, smashed a model American tank live on stage. He first holds the tank above his head, before throwing it to the floor and violently breaking it up with a microphone stand.

The demonstration happened during strong anti-American sentiment in the country after a 50-tonne U.S. armored vehicle killed two 14-year-old South Korean girls, Shim Mi-seon and Shin Hyo-sun, on their way to a birthday party.

Sergeants Mark Walker and Fernando Nino were in charge of the vehicle at the time of the accident and were charged with negligent homicide.

American military officials refused requests for the soldiers to be tried in South Korean courts.

When the two men were found not guilty by a U.S. military court in February 2002, it ignited massive anti-American protests. The memory of those two girls is commemorated annually in South Korea.

Then, two years later, a protest concert was held in Seoul after the killing of Kim Sun-il, a South Korean missionary and translator. He was beheaded by militants in Iraq after his country sent 3,000 troops to the region.

At this 2004 anti-war event, a group of musicians, including Psy, performed Dear American, a protest song written by Korean rock band N.E.X.T.

When it came to Psy's turn he rapped about "killing those f***ing Yankees who have been torturing Iraqi captives."

"Kill their daughters, mothers, daughters-in-law and fathers," the Daily mail quoted him as saying.